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Electrochemically converting waste nitrate (NO3−) into ammonia (NH3) is a green route for both wastewater treatment and high‐value‐added ammonia generation. However, the NO3−‐to‐NH3 reaction involves multistep electron transfer and complex intermediates, making it a grand challenge to drive efficient NO3− electroreduction with high NH3 selectivity. Herein, an in‐operando electrochemically synthesized Cu2O/NiO heterostructure electrocatalyst is proven for efficient NH3 electrosynthesis. In situ Raman spectroscopy reveals that the obtained Cu2O/NiO, induced by the electrochemistry‐driven phase conversion, is the real active phase. This electronically coupled phase can modulate the interfacial charge distribution, dramatically lower the overpotential in the rate‐determining step and thus requiring lower energy input to proceed with the NH3 electrosynthesis. The orbital hybridization calculations further identify that Cu2O is beneficial for NO3− adsorption, and NiO could promote the desorption of NH3, forming an excellent tandem electrocatalyst. Such a tandem system leads to NH3 Faradaic efficiency of 95.6%, a super‐high NH3 selectivity of 88.5% at −0.2 V versus RHE, surpassing most of the NH3 electrosynthesis catalysts at an ultralow reaction voltage. [ABSTRACT FROM AUTHOR]

Continuous miniaturization of semiconductor devices is the key to boosting modern electronics development. However, this downscaling strategy has been rarely utilized in photoelectronics and photovoltaics. Here, in this work, a full‐van der Waals (vdWs) 1D p‐Te/2D n‐Bi2O2Se heterodiode with a rationally designed nanoscale ultra‐photosensitive channel is reported. Enabled by the dangling bond‐free mixed‐dimensional vdWs integration, the Te/Bi2O2Se type‐II diodes show a high rectification ratio of 3.6 × 104. Operating with 100 mV reverse bias or in a self‐power mode, the photodiodes demonstrate excellent photodetection performances, including high responsivities of 130 A W−1 (100 mV bias) and 768.8 mA W−1 (self‐power mode), surpassing most of the reports of other heterostructures. More importantly, a superlinear photoelectric conversion phenomenon is uncovered in these nanoscale full‐vdWs photodiodes, in which a model based on the in‐gap trap‐assisted recombination is proposed for this superlinearity. All these results provide valuable insights in light–matter interactions for further performance enhancement of photoelectronic devices. [ABSTRACT FROM AUTHOR]

Due to excellent electrical and optoelectronic properties, 2D transition metal dichalcogenides and their van der Waals (vdW) heterostructures have attracted great attention for broadband optoelectronics. Here, an unreported vdW PdSe2/WS2 heterostructure is developed for robust high‐performance broadband photodetection from visible to infrared optical communication band. These heterostructure devices are simply formed by direct selenization of Pd films pre‐deposited on the chemical vapor deposited monolayer WS2, followed by wet‐transfer onto device substrates with pre‐patterned electrodes. Importantly, the obtained heterostructure device exhibits an impressive broadband spectral photoresponse with response times less than 100 ms for different wavelength regions (532 to 1550 nm), where this performance is significantly better than that of pristine monolayer WS2 devices. This performance enhancement is attributed to the type I band alignment of the heterostructure. Under illumination, both intralayer and interlayer excitations are involved to generate carriers in the relevant layer, enabling the broadband photoresponse. Photocarriers would then undergo charge separation in the depletion region with electrons transferred into the charge transport layer of WS2 through the built‐in electric field, followed by the relaxation to valance band via interlayer or intralayer transition. All these findings can indicate the promising potential of vdW PdSe2/WS2 heterostructures for next‐generation high‐performance optoelectronics. [ABSTRACT FROM AUTHOR]

Due to the multiple electronic transmission channels established at the interface between NiMo cores and C 3 N 5 shells, the obtained NiMo@C 3 N 5 hybrids exhibit stable and efficient HER performance in seawater, which is superior to that of commercial Pt/C. [Display omitted] • Multiple electronic transmission channels were established between NiMo and C 3 N 5. • Induced electron redistribution effect optimized the HER reaction pathway. • The NiMo@C 3 N 5 catalyst shows excellent HER performance and stability in seawater. Designing highly efficient and stable electrocatalysts for hydrogen evolution reaction (HER), particularly in seawater, still remains a challenging task. Herein, the unique heterostructures composed of 1D NiMo cores and 2D C 3 N 5 shells (NiMo@C 3 N 5) are rationally designed and demonstrated as the robust HER catalysts in both alkaline electrolytes and natural seawater, where the carbon-based shell can effectively protect the catalyst core from seawater poisoning. Based on the experimental investigation and density functional theory calculation, multiple electronic transmission channels were found to establish at the interface between NiMo cores and C 3 N 5 shells, thus providing efficiently optimized HER pathways to achieve minimized overpotential with a reduced energy barrier of the rate-determining step. More importantly, the NiMo@C 3 N 5 hybrids exhibit stable HER performance with a high Faradaic efficiency of 94.8% in seawater, which is superior to that of commercial Pt/C. All these results can evidently highlight a feasible strategy to develop high-performance HER electrocatalysts via interface engineering. [ABSTRACT FROM AUTHOR]